1. Field of the Invention
This invention is directed generally to image processing, and more particularly, to methods and systems for scaling and rotating an image in a single operation.
2. Description of the Related Art
Conventional scanners, printers, copiers and multifunction devices typically have the ability to scale an image to satisfy internal image pipeline requirements or to satisfy a user's desire to enlarge or reduce the image. Those devices also typically permit the rotation of an image to correct a rotation of the source image. The rotation might be due to user error in placing the source on the scanner, or it may come from mechanical tolerances when the page is fed using an Auto-Document Feeder (ADF). There may also be additional uses for a rotation function, such as aligning multiple input images to be printed on a single output page, or even user directed rotation of a source image.
If a source image needs to be both scaled and rotated, the traditional method would be to perform the operations separately in series. It is advantageous that a rotation be performed on a larger image to increase the quality of the output, which means that in order to achieve the best quality output document, the order of operations should be switched for an enlargement versus a reduction. However, this will consume more bandwidth than if the smaller image is the one being rotated, which negatively impacts the resultant quality of an output image. Additionally, where both scaling and rotation are implemented, the image will be subjected to two interpolation operations, which results in potentially significant quality reductions due to the performance of each operation individually.
Therefore, what is needed are methods and systems to rotate and scale an image as quickly and efficiently as possible while imparting minimal degradation to the quality of the output image.